Usage and Grammar

Q. Do you have the definitive word on the following: “A is 29% greater than B” (as, for example, when A costs $1.29 and B costs $1.00)? I’m bothered by the use of a percentage less than 100, immediately followed by the “greater than” phrase, which I think is self-contradictory. In this specific case, I think A is actually 129% greater than B. If A cost less than B, it would be some percentage less than 100; if it costs more, then it must be some percentage greater than 100. Any comments?

A. Yes. I’m afraid that the definitive word (from a University of Chicago mathematician) is: you are wrong. Sorry! But evidently the phrase “greater than” is not the same as “of” (which means “times,” mathematically speaking). So in this case “A is 129% of B” is the same as “A is 29% greater than B.” (If B is $1.00, then A is $1.29.) “A is 129% greater than B” would mean that to find A, you would have to add B + 129% of B. (If B is $1.00, then A is $2.29.)